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Avionics module 6
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Avionics module 6 Avionics module 6 Presentation Transcript

  • Automatic Flight Devinder K Yadav1
  • Automatic Flight Director System • Operating requirements of both autopilots and Flight Directors are very similar – Maintenance of performance parameters – Maintenance of flight path parameters both laterally and vertically • The automatic flight director system and flight control system are integrated and control can be changed seamlessly from one to the other. 2
  • Automatic Flight 3
  • Automatic Flight 4
  • Automatic Flight 5
  • Autopilot - Operation 6
  • Autopilot - Operation FCC –Flight Control Computer FMS – Flight Control System FCU –Flight Control Unit 7
  • Autopilot - Operation FCC –Flight Control Computer FMS – Flight Control System FCU –Flight Control Unit 8
  • Autopilot Classification • Single Axis • Two-axis • Three-axis 9
  • Modes of Autopilot • Control Wheel Steering (CWS) • Command (CMD) 10
  • Modes of Autopilot -CWS 11
  • Modes of Autopilot - CMD 12
  • Auto Pilot Components • Control • Signal processing • Servo systems • Sensing system • Disengagement warning 13
  • Yaw Damper • Dutch Roll • Correction of rudder system • Parallel type • Series type • Hand flying aircraft 14
  • Flight Director Switch • When turned ON: – Command bars are displayed in TO when on ground – Current values of VS and HDG HOLD are displayed if airborne – Current mode of autopilot displayed if it is engaged • When turned OFF: Removes the command bars from the associated EADI 16
  • Autopilot Switch • Will not engage unless ‘DISENGAGE’ switch is in UP position • Engaged by pressing the appropriate ‘L’, ‘R’ or ‘C’ switch • The centre switch is selected when in approach mode to facilitate all three autopilots engaging simultaneously for autoland to occur. • Autopilot is usually disengaged by a switch on the control column – which then sounds a horn that is silenced by pressing it again. 17
  • LNAV Mode • Armed autopilot captures and tracks the course entered in the FMC. • EADI shows track in white until captured, then in green. • Roll function control of the Attitude Flight Director System is transferred to the FMC System • If the aircraft is not on a heading to intercept the track the MSG light comes on and NOT ON INTERCEPT HDG is displayed on the CDU. 18
  • VNAV Mode • Engages the vertical mode of the FMS and transfers pitch and speed control of AFDS and autothrottle control to the FMC • Flies the vertical profile through climb, cruise and descent as determined by the FMC or modified by the pilots. • Cannot be engaged after take off if the Thrust Mode is in TO. 19
  • Heading Control • HOLD function causes the present heading to be maintained as the autopilot levels the wings • Heading Select sets the desired heading and positions the cursor on the EHSI • The aircraft can be steered while on autopilot by rotating the HDG SEL knob 20
  • Heading Control • Bank angles can be limited in association with the Heading Selector • AUTO limits the angle of bank to 15º when speed is above 250 knots, increasing progressively to 25º as the aircraft slows • Bank is not limited in VNAV mode 21
  • Altitude Hold •HOLD button commands the autopilot to hold present altitude. ALT HLD shows in pitch display •Knob is turned to the desired altitude and is directed to that altitude by using the FLCH or V/S in the pitch mode display. •When reached, ALT CAP appears in the pitch display. Caution lights appear if the A of A exceeds 6º while in ALT HLD or ALT CAP modes 22
  • Vertical Speed Control • With V/S selected the autopilot will maintain the vertical speed set in the V/S window • Altitude and Speed Hold are disconnected • This mode is often used for intermediate descents at a given rate or for ATC needs • It is the quickest way to initiate climbs or descents 23
  • Speed Control• Selected auto-throttle speed or Mach No is set in the window and held by A/T • Digits are changed by rotating the knob • IAS/Mach is interchanged by pressing SEL button • FLCH mode integrates AFD System and A/T for altitude change either at the existing speed or at the speed subsequently set after the mode is engaged • Disengages VNAV mode 24
  • ILS switching (LOC) LOC switch arms the localiser and the APP switch arms both localiser and glide slope 27
  • Localiser Capture 28
  • Capture Glideslope 29
  • Auto-Throttle • Accurately maintains selected flight parameters • Typical system maintains automatic thrust from start of take off, through climb, cruise, descent, approach and landing or go around. • Appropriate engine settings are commanded by the pilot or the settings in the CDU. 31
  • Autothrottle Limits Autothrottle provides pitch and thrust commands to prevent the following; • Exceeding maximum IAS or Mach No • Exceeding flap speed limits • Exceeding landing gear speed limits • Falling below minimum speed or allowing the angle of attack to exceed the Alpha floor35
  • Take Off (below 80 knots) 36
  • Take Off after 80 knots 37
  • Flight Level Change 38
  • MCP and EADI at Top of Climb 39
  • Vertical Speed mode 40
  • Approach Mode 41
  • MCP in Land Mode 42
  • Autoland • 1500 ft RA system ‘self test’ occurs. FLARE, LANDING and ROLLOUT are armed • 300 ft RA glideslope sensitivity is decreased • 200 ft RA longitudinal axis aligned • 100 ft RA alpha floor is inhibited (or aircraft wouldn’t flare) • 5 ft RA Go Around mode inhibited • Autoland Status Annunciators allow pilots to monitor the manoeuvre 43
  • MCP in Flare Mode 44
  • Autoland Failures • Fail operational system has the capability of tolerating the failure of one of the autopilots and still continue landing • Fail Passive systems will stop operating after the failure of an autopilot but the aircraft will remain in steady flight. • In both instances a warning of the failure is provided and shut down of the faulty system automatically made 46
  • Alerting Systems Devinder K Yadav1
  • Warning Systems Devinder K Yadav
  • 2 of 33 Ground Proximity Warning System  Purpose  To prevent controlled flight into terrain (CFIT)  CFIT mostly caused by  Distraction  abnormal situations  emergencies
  • 3 of 33 GPWS  Inputs:  radio altitude  airspeed/Mach No.  barometric altitude  landing gear position  flap position  glidescope deviations  and for windshear alerting, • angle of attack • acceleration (from IRS)
  • 4 of 33 GPWS  Generally two levels of warning  soft warning - cautionary  hard warning - alarm  aural warnings  synthetic voice  buzzer/horn  several modes of alert are illustrated on the next slide
  • 6 of 33 GPWS - Alert Modes Mode 1: Excessive Descent Rate  independent of aircraft configuration  becomes active below 2500’ RA  soft warning ‘SINK RATE’ repeated  hard warning ‘WHOOP WHOOP PULL UP’ also with PULL UP warning light
  • 9 of 33 GPWS - Alert Modes Mode 2: Excessive Terrain Closure  monitors airspeed, radio altitude, barometric altitude, vertical speed and configuration  Two sub-modes: 2A and 2B
  • 11 of 33 GPWS - Alert Modes Mode 2A  flaps down less than 25o  soft warning upper boundary depends on airspeed • 2450’ at >250 kt • 1650’ at <190 kt ‘TERRAIN TERRAIN’  hard warning ‘WHOOP WHOOP PULL UP’
  • 15 of 33 GPWS - Alert Modes Mode 3 - take off/go-around sink rate  gear and flaps selected  during take off  advisory only  loss of barometric altitude (sliding scale, approx 10% RA)  flaps raised at low RA  ‘DON’T SINK’
  • 21 of 33 GPWS - Mode 4A, 4B Mode 4A: cautions can be inhibited  Inhibition occurs when less than full flap for landing  e.g. when making asymmetric approach or with flap malfunction
  • 22 of 33 GPWS - Alert Modes  Mode 5: below glidescope  1.3 dots low on G/S, LOC signal received  below 1000’ RA  soft warning ‘GLIDESLOPE’  hard warning at 2 dots low below 300’ RA ‘GLIDESLOPE’ (louder)  Can be inhibited or cancelled
  • 25 of 33 GPWS - Alert Modes Mode 6: Minimums  The pilot programmes the GPWS with the RA minimums from the approach plate  ‘MINIMUMS MINIMUMS’  only with gear down  only values less than 1000’ RA can be set
  • 27 of 33 GPWS - Alert Modes Mode 7: Windshear  Inputs from  angle of attack  IRS accelerations  airspeed  ‘WINDSHEAR WINDSHEAR’  overrides all other GPWS modes from rotation to 1500’ RA
  • 29 of 33 Enhanced Ground Proximity Warning System (EGPWS) B767 Note:  The GPWS will neither provide a warning of flight toward vertically sheer terrain nor of slow descents into unprepared terrain while in the landing configuration  Predictive GPWS (enhanced GPWS)  has an inbuilt data base of terrain at GPS positions  provides better information regarding approaching terrain and can calculate the likelihood of collision in future  terrain information can be presented to pilot
  • 30 of 33 Flight Data Recorder Records:  time  altitude  airspeed  vertical acceleration (g)  heading  PTT activation  (another 14 items for new aircraft above 29 000 kg)
  • 31 of 33 Flight Data Recorder  Pitch attitude  Lateral acceleration  pitch trim  pitch, roll and rudder control or control surface position  leading edge device position  angle of attack  Roll attitude  thrust of each engine  flap position  longitudinal acceleration  undercarriage squat/tilt  thrust reverser position
  • 32 of 33 Flight Data Recorder  Records last 25 hours of data  New models called digital flight data recorders  Cockpit instrumentation:  FDR - warning light, test switch  CVR - warning light, test switch, erase button* *Erase only works on the ground with the parking brake set